This sensor is based on the MQ-9 sensor. Given a logical input, the sensor will produce an analog signal proportional to the concentration of hydrocarbon gases (propane, methane, n-butane) and carbon monoxide in the surrounding air gas (CO) in the air. Libraries for Arduino or Iskra are available to convert these readings into ppm (parts per million).
The sensor can be used to detect industrial gas leaks, fire, gas equipment malfunctions. Sensitivity can be adjusted using a trimmer on the sensor board.
A heating element is built into the module's gas analyzer, which is necessary for the chemical reaction to occur. Therefore, during operation the sensor will be hot - this is normal. Before using for the first time, we recommend that you "burn" the sensor. Turn it on and leave it running for 48 hours. This procedure will increase the accuracy of the sensor's readings. After this, stabilization after switching on will take about a minute.
For the sensor to work properly, the heating element must be alternately powered from 1.5 V (90 seconds), then from 5 V (60 seconds). Or, you can change the voltage in a sinusoidal pattern with a corresponding amplitude and area of the subgraph. When supplying from a low voltage the maximum sensitivity to carbon monoxide is reached and when operating in high voltage, hydrocarbon gases are measured and condensate is evaporated. If it is necessary to measure only carbon monoxide, it would be enough to only supply the sensor with 1.5 V.
When the sensor is connected to a microcontroller, different heater voltages can be simulated using a PWM signal.
Sensor readings are influenced by ambient temperature and humidity. Therefore, when using the gas sensor in a changing environment, if it is necessary to obtain accurate readings, filtering and compenstation is necessary.